Temperature compensation of fluxgate magnetometers

Based on the finding that the temperature dependence of fluxgate sensors is proportional to the measured field, a temperature compensation circuit is described using the copper resistance of the fluxgate secondary winding as the thermosensitive part of a bridge. The bridge voltage is derived from the magnetometer output so the compensation is only active in high fields.     

The limitation of the dynamic range of a spectrum analyzer due to nonlinear processes in the mixer

Theoretical formulas are obtained for estimating the relative levels of spurious “responses” of the output of a spectrum analyzer when the useful signal voltage, the heterodyne voltage, and interference simultaneously act at the input of the crystal mixer. __________ Translated from Izmeritel’naya Tekhnika, No. 7, pp. 57–59, July, 2008.     

高精密测温电桥的标定与评估

使用RTU和RBC两种精密仪器对中国计量科学研究院中温基准实验室的F900高精密测温电桥进行了标定和评估,分析了不同工作频率、不同输出电流在长杆标准铂电阻温度计测温范围内对测量精度的影响。结果表明:电桥在不同的工作频率下精度的差异比较明显。工作频率为25 Hz时,使用RTU和RBC进行标定的最大测量偏差分别约为0.01 mK和0.06 mK;工作频率为75 Hz时,使用RTU和RBC进行标定的最大测量偏差约为0.08 mK和0.2 mK,且相比出厂时有了较大的漂移。电桥在不同的输出电流下精度的差异非常小,在15 μK以内。采用RTU及RBC对F900测温电桥评价的结果之间相互印证,该结果对中温固定点基准复现过程的不确定度评定提供了数据支撑。     

Design of a platinum resistance thermometer temperature measuring transducer and improved accuracy of linearizing the output voltage

An improved method is presented for designing a temperature measuring transducer, the electrical circuit of which comprises an unbalanced bridge, in one arm of which is a platinum resistance thermometer, and containing a differential amplifier with feedback. Values are given for the coefficients, the minimum linearization error is determined, and an example is also given of the practical design of the transducer, using the given coefficients. A determination is made of the limiting achievable accuracy in linearizing the output voltage of the measuring transducer, as a function of the range of measured temperature.Translated from Izmeritel'naya Tekhnika, No. 1, pp. 48–50, January, 1995.     

Precision RF Voltage Standard Using a Thermistor Bridge Covering the HF-UHF Range

This paper describes a thermistor mount designed so that residual inductances of leads in the thermistor are eliminated for use in the UHF range. The output voltage of the thermistor bridge is evaluated by the dc substitution method with an accuracy of 0.3 percent for 0.3-1 V over frequencies up to 1.5 GHz. The output voltage agrees with the voltage derived from power and impedance standards within the accuracy.     

Linearized Thermistor Multivibrator Bridges for Temperature Measurement

Methods for output voltage linearization of a thermistor astable multivibrator bridge (AMB) and a monostable multivibrator bridge (MMB) are given. In addition to higher sensitivity in comparison with Wheatstone bridge, thermistor multivibrator bridges can have direct application in telemetering and digital recording of temperature. The linearity condition of thermistor AMB and MMB are independent of indicator resistance. Experimental multivibrator bridges with IC differential transistor pairs have shown excellent stability at ambient temperature variations.     

Investigation of the error in transferring the dimensions of the volt using a transportable stabilitron voltage standard

The results of an investigation of the characteristics of transportable voltage standards based on stabilitrons for the purpose of using them as standards of comparison when transferring the dimension of the unit of constant voltage in accordance with the State Standard GOST 8.027-2001 are presented. It is shown that, using the standard investigated, one can transfer the dimensions of the unit of voltage with an overall relative error of 5·10⁻⁸ for a voltage of both 1.018 V and 10 V. __________ Translated from Izmeritel'naya Tekhnika, No. 1, pp. 34–38, January, 2006.     

Cryogenic operation of FinFETs aiming at analog applications

FinFETs are recognized as promising candidates for the CMOS nanometer era. In this paper the most recent results for cryogenic operation of FinFETs will be demonstrated with special emphasis on analog applications. Threshold voltage, subthreshold slope and carrier mobility will be studied. Also some important figures of merit for analog circuit operation as for readout electronics, such as transconductance, output conductance and intrinsic voltage gain will be covered. It is demonstrated that the threshold voltage of undoped narrow FinFETs is less temperature-dependent than for a planar single-gate device with similar doping concentration. The temperature reduction improves the transconductance over drain current ratio in any operational region. On the other hand, the output conductance is degraded when the temperature is reduced. The combination of these effects shows that the intrinsic gain of a L = 90 nm FinFET is degraded by 2 dB when the temperature reduces from 300 K to 100 K.     

Transistorized instrument for remote measurement and control of temperature

Conclusions The preceding thermoregulator uses transistors and crystal diodes in addition to thermistors, thus eliminating completely electron tubes from the circuit, and ensuring reliable operation of the relay even for weak signals received from the bridge output. The transistorized thermoregulator is not inferior to electron tube regulators with respect to control accuracy, but it is considerably smaller and lighter than the latter. The response of the thermoregulator to weak bridge signals makes it possible to use not only thermistors type MMT-4 in the bridge circuit, but also type MMT-6, which are microthermistors whose small dimensions provide the measurement and control of temperature at a given point. Translated from Izmeritel'naya Tekhnika, No. 11, pp. 23–27, November, 1961     

Investigation of low-temperature plasma generator with divergent channel of the output electrode and some applications of this generator

A review is made of experimental and theoretical investigations of processes occurring in low-temperature plasma generators (LTPG) with divergent channel of the output electrode, and the possibilities of utilizing these generators in new plasma technologies are analyzed. Comparison is made of the characteristics of discharge (including the current-voltage characteristic) in a divergent channel and in a cylindrical channel of uniform cross section. The effect of divergent channel of the output electrode and of its expansion ratio on the pattern of physical processes in LTPGs of different designs is studied. Investigations are performed of the distribution of electric current and heat flux density along a channel with a segmented output electrode. The voltaic equivalents of heat fluxes to cathode and anode are determined. The process of “shunting” of discharge is investigated, which causes fluctuations of electric arc-burning voltage. The investigations involving an LTPG with divergent channel reveal that the voltage amplitude in the case of shunting decreases with increasing current strength and, at high currents of argon arc, does not exceed 1–2 V. Results are given of spectral and visual investigations of LTPG. It is demonstrated that, in an LTPG with divergent channel, the plasma temperature in the region of energy input at currents of 300 A and higher exceeds 30 000 K. The significant part is found which is played by vacuum ultraviolet radiation in the process of closing the arc to anode. The mechanisms of erosion of the tungsten cathode tip are investigated, which play an important part in increasing the cathode service life by way of recirculation of tungsten atoms because of their ionization in the discharge gap. Results are given of using an LTPG with divergent channel of the output electrode in plasma technologies of surface hardening, cutting, and hard-facing of metals. The technology of plasma hardening of wheel pairs, adopted by the RZhD (Russian Railroads) Joint-Stock Company, provides for increasing the service life of railroad wheels by a factor of 1.5–2.     

Measurement of the VSWR at the output of high-frequency generators under “hot conditions”

A simple method of measuring the voltage standing-wave ratio at the output of high-frequency generators is considered. __________ Translated from Izmeritel’naya Tekhnika, No. 9, pp. 55–56, September, 2006.     

A simple accurate bridge-transducer interface with continuousautocalibration

This paper presents a one-chip simple and accurate transducer interface for resistive bridges. A key part of this interface is formed by a novel dynamic voltage divider. In this divider the bridge supply voltage is measured for reference purposes in small parts (piece-wise measurement) which are within the range of the bridge output voltage. The use of an autocalibration technique, the three-signal method, eliminates influeuce of linear parameters and errors. Moreover, the effects of the nonidealities of the applied switches are also eliminated. The circuit has been realized in a 3 μm BiCMOS process and shows an uncertainty of only 10 μV for a bridge supply voltage of 5 V     

Monostable Multivibrator as the Bridge Circuit with Linear Characteristic

A monostable multivibrator, triggered by pulses of constant frequency, can be used as a bridge circuit either with capacitance or resistance transducers. The output voltage of the monostable multivibrator bridge is a linear function of transducer impedance. Sensitivity is four times higher compared with the Wheatstone bridge.     

微型流量传感器研究

目的　研究微型管道的流量测量技术 .方法　采用热膜技术 ,在石英玻璃棒上镀一层铂电阻膜 ,利用激光将铂膜蚀刻成特定的形状 ,形成 4个独立的铂电阻 ,并构成一基本的电桥 ,电桥通以一定的电流后产生热量 ,由于液体流动的作用会使 4个铂电阻间产生一定的温差 ,从而导致电桥失衡 ,产生一定的输出电势 .结果　研制出的流量传感器的各项技术指标满足设计要求 .结论　微型流量传感器与传统的传感器相比 ,在性能上有了较大的提高 ,并且具有对管道中液体压力损失小的特点     

A compact comparison standard based on the Josephson effect with an output voltage of 10 V

A compact comparison standard in the form of a voltage measure based on the Josephson effect with an output voltage of 10 V is developed. The purpose of the standard is to carry out international comparisons of stationary standards of the volt based on the Josephson effect and provide traceability of the measurements made using the Russian State Primary Standard of the volt, with the BIPM standard of the volt with a relative uncertainty of less than 2⋅10⁻¹⁰. The comparison standard apparatus is placed in a case which protects it when it is transported.     

Increasing the voltage output of a Wheatstone bridge having one or two active strain gauge arms

A method of increasing the voltage output of a Wheatstone bridge having one or two active arms is discussed. An increase of 80% is shown to be practicable without increasing the current in the gauge. This is achieved by using an asymmetrical bridge configuration instead of the more usual symmetrical arrangement. The effect of this configuration on output linearity is considered and a bridge-balancing circuit is illustrated.     

灼热桥丝式电点火药头的发火时间变化规律研究

使用F10数码电子雷管发火测试仪,研究苦味酸钾系电点火药头的发火时间与电容器的输出电压、桥丝直径之间的关系,并通过高速摄影仪拍摄药头的燃烧状况。试验结果表明:在可测试电压范围内,数码电子雷管电点火药头的发火时间随着输出电压的增大而逐渐减小,发火时间极差和标准差也逐渐减小;输出电压大于15.0 V后,苦味酸钾系电点火药头的平均发火时间稳定在0.42 ms左右,发火一致性很高;直径较小的桥丝电阻较大,桥丝与点火药剂之间的传热效率好,有利于提高电点火药头的瞬发度和发火可靠性;苦味酸钾系电点火药头的火焰明亮,药剂燃烧充分,燃烧时间较长（百毫秒级）,点火能力可靠。     

Method of temperature error compensation in strain transducers

A method of compensation for the temperature error of semiconductor bridge strain transducers is described. It is based on the use of a strain gage bridge as the temperature-sensitive element and controllable source of current for supply to the bridge. The supply current is regulated to compensate for variation in temperature sensitivity in relation to bridge resistance by means of positive feedback while a correcting voltage proportional to the temperature is formed for correcting zero drift. The method facilitates the temperature error of strain transducers to be reduced up to 0.5% at 70–80°C.Translated from Izmeritel'naya Tekhnika, No. 7, pp. 39–40, July, 1993.     

Cryogenic temperature measurement for large applications

We have developed a resistance thermometry system for the acquisition, control and monitoring of temperature in large-scale cryogenic applications. The resistance of the sensor is converted to a voltage using a self-balancing AC bridge circuit featuring square-wave excitation currents down to 1 nA. The system is easily scalable and includes intelligent features to treat special situations such as magnet quenches different from normal operation.     

Establishment of traceability for strain measuring data acquisition system in terms of voltage

This paper emphasizes on establishment of traceability for the strain measuring data acquisition system in terms of voltage. If this amplifier’s output voltage is not calibrated then traceability chain breaks. To complete the traceability chain, the amplifier’s output voltage has been calibrated for corresponding strain. The sensitivity is calculated using calibration results and further used to feed in data acquisition system to display the result in terms of force/strain.